1. Field of the Invention
The present invention relates to a new process for modifying the surface condition of the most diverse materials. It relates more particularly to a new relief offset printing process.
2. Description of the Prior Art
The multiple facilities for producing offset blocks and plates, the flexibility offered by the mounting for page setting, the ease of storing films and type molds, the possibility of printing in colors on relatively ordinary media, explain the importance of offset in the printing of packings, catalogs, periodicals, books, etc. Rotary offset printing allows printing to be carried out without pressure on practically all surfaces. Offset inks must satisfy a very lage number of physio-chemical requirements and have defined flow, coloring and drying properties on the support medium, they must without accident play their role as water repellent substances in dynamic balance with the water and the plate. Because of the rotary movement of offset presses which allows much higher speeds than the reciprocal movement of lithographic presses, for example, the offset process has taken its place among the great printing processes. However, this process has an important drawback: the surfaces thus treated and printed have after drying an absolutely uniform relief. If it is desired to obtain a less uniform, more heterogeneous, and more artistically decorated surface, in accordance with the presently known techniques, recourse must be had to compliated and costly procedures such for example as mechanical deformations of the support medium. Furthermore, the different support media and surfaces must be able to withstand these different mechanical stresses. Other techniques such as flocking, the use of inks containing swelling agents and a succession of a plurality of silk screen impressions given unsatisfactory results or are economically very expensive or else can only be applied to perfectly flat surfaces.
The aim of the present invention is then to provide a relief offset printing process which answers better the requirements of practice than the processes known heretofor and used for the same purpose, more especially in that it allows relief to be obtained of as large a variety as desired, in that it may be applied to all surfaces and all materials and in that it is simple, easy and economical to carry out.